Ajax Module Popup Box

<cc1:ModalPopupExtender ID="ModalPopupExtender1" runat="server" CancelControlID="btnCancel"
TargetControlID="btnPopup" PopupControlID="pnlTrackingNr" PopupDragHandleControlID="PopupHeader"

Drag="false" BackgroundCssClass="ModalPopupBG">
</cc1:ModalPopupExtender>
<asp:Panel ID="pnlTrackingNr" Style="display: none" runat="server" HorizontalAlign="Center"
Width="300px" Height="50px" BackColor="WhiteSmoke" BorderColor="#659FD9" BorderWidth="2px" BorderStyle="solid">
<div>
<div id="PopupHeader" style="background: #91B7E7; border-color: #659FD9; color: White;">
<b>Please Confirm</b></div>
<div class="Controls">
<table id="tblWarehouses" width="100%">
<tr valign="top">
<td>
<asp:Label ID="lblWarning" runat="server" CssClass="displayfont"></asp:Label>
</td>
</tr>

<tr>
<td colspan="2">
<asp:Button ID="btnYes" Text="Yes" runat="server" CssClass="button" OnClick="btnYes_Click" />
<input id="btnCancel" type="button" class="button" value="No" />
</td>
</tr>
</table>
</div>
</div>
</asp:Panel>